Every transaction changes the balance in your account and as the bank gets new accounts or closes existing ones, that database must be updated to reflect accurately such changes as they happen.
Both Memcached, which accelerates existing relational databases like MySQL, and Redis, which is a complete, stand-alone database and acceleration solution, are open source technologies.
The two million people already signed up to the London 2012 ticketing database will receive information about how to apply, with registered users being able to use their existing log-in details.